state,worker/provisioner: fix test timeouts
A couple of places that were relying on testing.ShortWait
to wait for something to happen.
There are a few more, but this should help matters
for the time being.
https://code.launchpad.net/~rogpeppe/juju-core/343-fix-test-timeouts/+merge/176155
(do not edit description out of merge proposal)